Hydraulically actuated tool



July 30, 1963 c. E. HOADLEY 3,099,135

HYDRAULICALLY ACTUATED Toor.

Filed Feb. 25, 1957 v V HF- T wrlnl l-v- -v---1 I I: FL i-1 44H50 L: EN

I se

INVENTOR.

\ n @rumba/Mz@ 3,099,135 HYDBAULICALLY ACTUATED TOOL Cyrus Earl Headley, Kankakee, Ill., assigner to Manco Mfg. Co., Bradley, Ill., a corporation of Illinois Filed Feb. 25, 1957, Ser. No. 642,083 7 Claims. (Cl. en -s2) 'Ilhe present invention relates to novel cutting or punching apparatus and the like, and more particularly to a novel apparatus for cutting, punching or similarly Working of relatively hard material such as metal by means of a hydrauhcally actuated tool.

While apparatus utilizing various hydraulically actuated tools may be improved in accordance with the present invention, the disclosure will be directed particularly to cutting apparatus for the purpose of facilitating illustration of the invention.

The apparatus contemplated herein comprises a tool having a piston actuated blade, which tool is connected by a hose or pipe to a pump or other source of hydraulic lluid under high pressure. The pump is continuously driven and means is provided for recirculating the iluid between work cutting operations. During a work cutting operation, the tool is associated with =a workpiece and then operated so that .the blade is forced through the workpiece. yIt has `been found that at the instant the blade breaks through the material of the workpiece the rate of travel of the blade or ram and piston connected thereto is sharply accelerated and the tool is subjected to a shock. As a result the useful working life of the tool is reduced and maintenance time and cost are substantially increased. It has been found that the sudden acceleration of the piston and lblade is caused by a. sudden inrush of hydraulic fluid into the piston chamber when the resistance of the workpiece is broken. This inrush of hydraulic fluid or oil when the system is operated under high iluid pressures may be at a rate far in excess of the normal delivery rate of the pump so that the piston is driven sharply against an internal stop in the tool. The high rate of oil oW results from the fact that the compressibility of the oil andthe expansion of the hose or pipe under high pressures combine to act as an accumulator which is capable of `delivering oil instantaneously at a high rate when the tool breaks through the workpiece so that the cutting pressure lis instantaneously relieved.

It is an important object of the present invention to provide a novel `apparatus of the above described type, which apparatus is constructed so as substantially to reduce or eliminate any undue shock to the tool when the resistance of the workpiece is broken.

A more specific object of the present invention is to provide a novel apparatus of the above described type including a hydraulically actuated tool, which tool is constructed so las to limit the rate of flow of hydraulic iluid under pressure thereto suiiiciently to eliminate `any undue shock -to the tool when the resistance of the workpiece is broken.

Another more specific object of the prese-nt invention is to provide a novel apparatus of the type mentioned in the preceding paragraphs wherein means is provided for limiting inrush of hydraulic iiuid to the piston of the tool while at the same time the apparatus is constructed so that at the end of a cutting operation or the like, the hydraulic fluid may be quickly discharged to facilitate rapid return of the tool pis-ton.

Other objects and advantages lof the present invention will become apparent from the following description and the accompanying drawings wherein:

FIG. l is an elevational view showing an apparatus incorporating the features of the present invention;

FIG. 2 is an enlarged fragmentary longitudinal partial atet "ice

sectional view taken in a ventical plane of the apparatus shown in FIG. 1;

FIG. 3 is a fragmentary partial sectional view taken along substantially the same plane as FIG. 2 lbut showing a modilied form of the present invention; and

FIG. 4 is a fragmentary partial sectional view similar to FIG. 3 but showing a further slightly modied form of the present invention.

Referring now lmore specifically to the drawings wherein like parts are designated by the same numerals throughout the various figures, an apparatus 10 incorporating the features of the present invention is shown in FIGS. 1 and 2. The apparatus comprises a tool generally designated bythe numeral 12, which tool is shown in the form of Ia rod cutter for .the purpose of illustrating the present invention, but it is to be understood that the apparatus might also include various types of hydraulically actuated cutters, punches, 'and the like. A unit 14 is provided for supplying hydraulic fluid or oil under pressure to the tool 12, Which unit includes a reservoir 16, a pump 18 and a motor 20 drivingly connected with the pump. The apparatus is provided with control valve means 22 which in this embodiment is a portion of the tool 12. The valve means or assembly 22 h-as an inlet port 24 connected by a hose or pipe 26 to an outlet 28 of the pump. An out let 30 of the valve assembly is connected Iby a pipe or hose 32 to the reservoir. The tool .12 includes a main body or cylinder 34 having a body member 36 of the valve assembly secured thereto by means of an adapter ring 38 into which a reduced diameter portion 40 of the valve body is threaded and a nut member 42 threaded onto the body 34 and overlying the adapter ring. A head assembly 42 is secured to the opposite end of the cylinder 34 and carries a tixed blade 44. A piston 46 is slidably disposed in the chamber within the cylinder 34 and is connected to a ram 48 lwhich in turn is connected to or integral with a movable blade l50. Springs -52 are provided for urging the piston toward the position shown in (FIGS. 1 and 2 so as to open the blade 50. A passageway 54 is provided through the valve body 36 so that when the control valve is actuated in the manner described below, hydraulic oil under pressure is introduced into the piston chamber so as to shift the piston against the action of the springs 52 and force the cutting blade 50 through a workpiece,

The valve assembly 22 is provided with a valve seat 56 in the outlet opening 30, and :a valve member 58 is slidably disposed in a bushing 60 opposite the outlet opening for engaging the valve seat. A flange 64 on the valve member is engageable with the bushing for limiting outward movement of the valve member. A pin 66 formed integrally with the valve member `53 extends outwardly of the valve body through an aperture in the base of a bracket 68 to which bracket an actuating handle -70 is connected by pivot pin 72. The valve member is urged to its open position by a spring 73. With the valve member 458 opened, hydraulic iluid entering the port -24 will circulate back to the reservoir 16 without actuating the piston. When it is desired to actuate the piston 46 and the blade member 50, the handle 70 is depressed for shifting the valve member 58 to engage the valve seat 56 so that hydraulic tluid under pressure will be delivered through the passageway 54 to the piston.

It is important to note that in the passageway '54, preferably immediately adjacent the piston chamber, there is provided a member 76 which is threaded into an end portion of the passageway 54 and which is provided with a restricted orifice 78. The apparatus with the restricted orice means therein is operated in the following manner. The motor 2t) and pump driven thereby are operated continuosly so that with the operating handle 70 in the raised position shown in FIGS. l and 2, hydraulic fluid is continuosly circulated through the hose or pipe 26 to the valve body 22 and back to the reservoir through the hose or pipe '32. Valve means 80 is provided in the pump assembly for controlling the pressure of the hydraulic lluid delivered through the pipe or hose 26 to the valve body 22. it will be understood that this fluid pressure may be varied as desired. By way of example, the apparatus is frequently operated with the lluid pressure set between 8000 p.s.i. and 9000 p.s.i. Then with a workpiece, not shown, located between the blades 44 and 50, the handle 70 is depressed so .as to close the valve member 58 'whereby iluid under pressure is directed through the passageway `54, and the restricted orifice `78 into the piston chamber. The workpiece provides substantial resistance to the movement of the blade 50 therethrough so that the fluid pressure builds up to the high pressures mentioned above and as a result, the hydraulic lluid or oil is slightly compressed and the high pressure fluid conduit means including the hose or pipe 26 is expanded. Then las the blade `50 breaks through the workpiece, the resistance or back pressure provided by the workpiece is sharply reduced so that there is a tendency for the hydraulic oil instantly to expand to its normal volume and for the cond-uit means including the hose or pipe 26 instantly to contract to its normal condition and thereby rapidly force a relatively large volume of hydraulic oil into the piston chamber which action would result in a sharp acceleration of the piston and forcing of the piston with considerable impact against an internal stop generally designated by the numeral -82 in FIG. 1. However, this surge of the hydraulic oil is prevented by the restricted orifice member 76 4which is constructed so as to limit the rate of flow of oil therethrough to a rate which will be insufficient to force the piston against the stop f82 with an impact force great enough to cause material damage to the tool. It will be noted that the orifice member is located adjacent the piston chamber so that the volume of hydraulic iluid between he orifice member and the piston, even when such hydraulic lluid is slightly compressed, is insuflicient by itself to cause undue acceleration of the piston. It will be appreciated that the size of the orifice 7'8 may be varied in different sizes of tools but it is understood that the size of the orifice will be such that the llow rate of hydraulic fluid therethrough will be limited in the manner described above. By way of example only, it has been found that for a tool of the size shown in full scale in FIG. 2, the orilice l78 will perform its function if it is formed with a diameter of about 3/16 of an inch. In any event, the orifice 78 is considerably smaller in diameter than the internal diameter of the hoses or pipes or the diameters of the remaining fluid passageways so that the hydraulic liquid may flow freely through such hoses or pipes and passageways without undue pressure drops or power losses. When a cutting operation is completed, the actuating handle -70 is released to permit opening of the valve '58. This causes the pressure in the piston chamber to be relieved, and the piston is returned by the springs 52 back against the stop provided by the adapter ring 38. `It will be lappreciated that the rate of return of the piston will be limited b y the `rate of fluid ilow back through the orifice '7-8. However,

this rate of return will be rapid enough for most installations.

In FIG. 3 there is .a fragmentary showing of a modified embodiment of fthe present invention. The structure of this embodiment is identical to the structure described above `except for the portion of the structure shown in FIG. 3. More specifically, this embodiment comprises a valve body 84 corresponding to the valve body 36 described above and having a lluid passageway y86 therethrough corresponding to the above described passageway 54. Restricted orifice means providing communication between the piston chamber 'and the passageway 86 is formed by passageways 88 and 90 drilled in the valve body 84, the passageway 90 having its outer end closed by 4a plug 92. Another plug 94 is turned into an enlarged threaded portion of the passageway S6, and this plug has an opening 95 substantially larger than the restricted orifice and a valve seat 96. A ball valve 98 is disposed for engagement with the Valve seat 96. The operation of this embodiment is similar to that of the structure described above in that during a work cutting operation, the check valve 93 is closed and fluid is directed into the piston chamber through the restricted orifice which bypasses the check valve. However, when the cutting operation is completed, more rapid return of the piston and blade co-nnected thereto may be -accomplished since the pressure provided by the springs returning the piston overcomes the pressure holding the check valve against the valve seat so that the valve is opened and the fluid may flow freely from the piston chamber.

FIG. 4 shows another modification of the present invention which is similar to the embodiment of FIG. 3 in that a check valve is provided for permitting rapid return of the piston and restricted orifice means is provided for bypassing the check valve to permit restricted fluid flow to the piston chamber. In this embodiment, a valve body 100 having a passageway 102 is provided, which valve body corresponds to the valve bodies 36 and 84 described above. Amember 104 is threaded into the body 100 and provides a check valve seat 106 corresponding to the check valve seat 96 described above. A check valve member or ball 108 is disposed for engagement with the seat 106. In this embodiment, the restricted orice means is provided by one or more shallow grooves 110 formed in the valve seat 106 so that when the valve member 108 engages the valve seat a restricted llow of hydraulic fluid may leak past the valve member.

While the preferred embodiments of the present invention have been shown .and described herein, it is obvious that many structural details may be changed without departing from the spirit and scope of the appended claims.

The invention is claimed as follows:

l. A hydraulic apparatus of the type described cornprising a tool including a member adapted to be forced through a workpiece, a hydraulically operated spring returned piston connected with said member for actuating said member and reciprocably disposed in a piston chamber, a remotely located hydraulic fluid reservoir, continuously operable pump means connected with said reservoir for continuously supplying hydraulic iluid under high pressure, valve body means located between said pump means and said piston chamber and substantially at said piston chamber, said valve body means including an inlet port, an outlet port and a third port communicating with said inlet and outlet ports, said outlet port being Sulliciently large as compared with said inlet port for providing for substantially free fluid llow from said inlet port through said outlet port, a pair of conduit means respectively connecting said pump to said inlet port and said outlet port to said reservoir, the conduit means connecting said pump and -said inlet being resiliently expandable under high fluid pressure produced by said pump during actuation of the piston, passageway means extending from said third port to adjacent said piston chamber, restricted orifice means immediately adjacent said piston chamber and connecting said passageway means to said piston chamber and being smaller than said outlet port for preventing sudden surges of hydraulic fluid into said piston chamber, and a normally opened valve member shiftable for `closing said outlet port for directing hydraulic fluid under high pressure through said passageway means and said restricted orifice means to said piston chamber for actuating said piston.

2. An apparatus, as delined in claim l, wherein said conduit means and said passageway means have predetermined relatively large diameters for facilitating flow of hydraulic fluid therethrough, and wherein said restricted orifice means has a diameter substantially smaller than the diameter of any of said conduit means and passageway means.

3. An apparatus, .as dened in claim 1, which includes means providing a valve seat defining .an opening between said passageway means and said piston chamber having an -area 4substantially greater than .a transverse cross sectional area of said restricted orifice means, and a check valve member engageable with said valve seat for directing hydraulic lluid from said passageway means through said restricted orice means to the piston chamber and for permitting flow of hydraulic uid from the piston chamber back through said opening to said passageway means to facilitate more rapid return of the piston.

4. A hydraulic tool of the type described comprising a member adapted to be forced through a workpiece, cylinder means providing a piston chamber, a piston connected with said member for actuating said member and reciprocably disposed in said piston chamber for operation by hydraulic fluid under pressure in one direction for advancing said member, spring means within said cylinder means and engaging sai-d piston means tEor biasing the piston means in the opposite direction, valve body means assembled with said cylinder means and including hydraulic fluid passageway means having a relatively large predetermined diameter connected with said cylinder means and having lan inlet and an outlet respectively connectable with a sour-ce of hydraulic lluid under high pressure an'd with a uid reservoir, `an open valve mem- Iber shiftably mounted in said Valve body means for closing said outlet -for directing fluid to said piston chamber and means providing a restricted orifice substantially at said piston chamber and connecting said passageway means to said piston chamber, said restricted orice having -a transverse cross sectional area substantially smaller than the transverse cross `sectional `area of said passageway means for restaining sudden surges of hydraulic lluid 6 under pressure `from said passageway means into said piston chamber.

5 A tool, `as idened in claim 4, which includes valve seat means defining an opening substantially at said chamber and connecting said piston chamber and said passageway means and having an `area substantially greater than the transverse area of said `orice means, and la check valve member engageable with said valve seat for directing hydraulic lluid under pressure from said passageway mean-s through said restricted orifice means into the piston chamber and for permitting rela-tively rapid return ow' of hydraulic fluid from the piston chamber through said opening to said passageway means.

6. A tool, as ldened in `claim 5, wherein said restricted orifice means is provided by sm-all diameter bore means extending between said passageway means and said piston chamber in ,bypassing relationship with respect to said valve seat.

7. A tool, las dened in claim 5, wherein said restricted orice means is provided by groove means in' said valve seat.

References Cited in the file of this patent UNITED STATES PATENTS 577,489 Mills Feb. 23, 1897 1,334,281 Constantinesco Mar. 23, 1920 2,067,492 Kingsbury Ian. 12, 1937 2,273,171 Bennett Feb. 17, 1942 2,344,133 Davis Mar. 14, 1944 2,360,070 Meyerbach Oct. 10, 1944 2,374,400 Westervelt Apr. 24, I1945 2,481,020 Justus Sept. 6, 1949 2,602,294 Sedgwick July 8, 1952 FOREIGN PATENTS 239,475 Great Britain Dec. 11, 1924 

1. A HYDRAULIC APPARATUS OF THE TYPE DESCRIBED COMPRISING A TOOL INCLUDING A MEMBER ADAPTED TO BE FORCED THROUGH A WORKPIECE, A HYDRAULICALLY OPERATED SPRING RETURNED PISTON CONNECTED WITH SAID MEMBER FOR ACTUATING SAID MEMBER AND RECIPROCABLY DISPOSED IN A PISTON CHAMBER, A REMOTELY LOCATED HYDRAULIC FLUID RESERVOIR, CONTINUOUSLY OPERABLE PUMP MEANS CONNECTED WITH SAID RESERVOIR FOR CONTINUOUSLY SUPPLYING HYDRAULIC FLUID UNDER HIGH PRESSURE, VALVE BODY MEANS LOCATED BETWEEN SAID PUMP MEANS AND SAID PISTON CHAMBER AND SUBSTANTIALLY AT SAID PISTON CHAMBER, SAID VALVE BODY MEANS INCLUDING AN INLET PORT, AND OUTLET PORT AND A THIRD PORT COMMUNICATING WITH SAID INLET OUTLET PORTS, SAID OUTLET PORT BEING SUFFICIENTLY LARGE AS COMPARED WITH SAID INLET PORT FOR PROVIDING FOR SUBSTANTIALLY FREE FLUID FLOW FROM SAID INLET PORT THROUGH SAID OUTLET PORT, A PAIR OF CONDUIT MEANS RESPECTIVELY CONNECTING SAID PUMP TO SAID INLET PORT AND SAID 